ircd-hybrid-7.2/include/dalloca.h

/* dalloca.h - alloca function for tinycc which doesn't have one natively
 * $Id: dalloca.h,v 1.2 2003/06/01 01:01:47 joshk Exp $
 */

/*
 *    Copyright (C) 2003 Damian M Gryski <dgryski@uwaterloo.ca> 
 *    Released under LGPL 2.1
 */

#ifdef __TINYC__

#ifdef NO_ALLOCA_CHECK
#define alloca_assert(expr)
#else 
#include <assert.h>
#define alloca_assert(expr) assert(expr)
#endif

/*
 * `size' is known at compile time, but tccasm doesn't like the math expr.
 * Blindly accept input, but at least assert() that it's good.
 * Since the assert() check is substantially more expensive than the alloca
 * itself, the check can be turned off by compiling with -DNO_ALLOCA_CHECK
 */

#define alloca_const(size) \
   ({ void * __sp; \
    alloca_assert(size % 4 == 0); \
   asm("subl $" #size ", %%esp\n"  \
       "movl %%esp, %0" \
       : "=m" (__sp) ) ; \
      __sp; })

#define alloca_var(size) \
   ({ void * __sp; unsigned int __arg = size; \
   asm("movl %1, %%eax\n"        /* get the size */ \
       "addl $3, %%eax\n"        /* eax := (eax + 3) & -4 */ \
       "andl $-4, %%eax\n"       /* rounds to next multiple of 4 */ \
       "subl %%eax, %%esp\n"     /* adjust stack pointer */ \
       "movl %%esp, %0\n"        /* return result */  \
       : "=m" (__sp) : "m" (__arg) : "eax") ; \
   __sp ; }) 


#define alloca(size) alloca_var(size)

#endif
Revision:	30
Committed:	Sun Oct 2 20:03:27 2005 UTC (20 years, 10 months ago) by adx
Content type:	text/x-chdr
Original Path:	*ircd-hybrid/include/dalloca.h*
File size:	1362 byte(s)
Log Message:	- imported sources - can be moved later according to the directory/branching scheme, but we need the svn up
#	Content
1	/* dalloca.h - alloca function for tinycc which doesn't have one natively
2	* $Id: dalloca.h,v 1.2 2003/06/01 01:01:47 joshk Exp $
3	*/
4
5	/*
6	* Copyright (C) 2003 Damian M Gryski <dgryski@uwaterloo.ca>
7	* Released under LGPL 2.1
8	*/
9
10	#ifdef __TINYC__
11
12	#ifdef NO_ALLOCA_CHECK
13	#define alloca_assert(expr)
14	#else
15	#include <assert.h>
16	#define alloca_assert(expr) assert(expr)
17	#endif
18
19	/*
20	* `size' is known at compile time, but tccasm doesn't like the math expr.
21	* Blindly accept input, but at least assert() that it's good.
22	* Since the assert() check is substantially more expensive than the alloca
23	* itself, the check can be turned off by compiling with -DNO_ALLOCA_CHECK
24	*/
25
26	#define alloca_const(size) \
27	({ void * __sp; \
28	alloca_assert(size % 4 == 0); \
29	asm("subl $" #size ", %%esp\n" \
30	"movl %%esp, %0" \
31	: "=m" (__sp) ) ; \
32	__sp; })
33
34	#define alloca_var(size) \
35	({ void * __sp; unsigned int __arg = size; \
36	asm("movl %1, %%eax\n" /* get the size */ \
37	"addl $3, %%eax\n" /* eax := (eax + 3) & -4 */ \
38	"andl $-4, %%eax\n" /* rounds to next multiple of 4 */ \
39	"subl %%eax, %%esp\n" /* adjust stack pointer */ \
40	"movl %%esp, %0\n" /* return result */ \
41	: "=m" (__sp) : "m" (__arg) : "eax") ; \
42	__sp ; })
43
44
45	#define alloca(size) alloca_var(size)
46
47	#endif